AC vs 12 volt for a Newby

[McFish1951]

It seems like maybe I need both. I need to run a CPAP nightly, as well as a fan. If I have shore power, I can bring an extension cord in and plug a charger to a power strip with a breaker. Make it a lithium charger to keep a 200 AH lithium full? And I can run 12 V off battery to power vent/fan and lights? If I'm boondocking, I need an inverter to run CPAP. I would plan on solar later to keep battery charged. CPAP uses about 36 AH for 8 hours. Is all of this basically plug and play? If not, where do I learn more? I would guess this has already been addressed somewhere?

[tony.latham]

Obviously, you've got several questions wrapped like a rope in your post. I'll take a couple--one at a time.

And I can run 12 V off battery to power vent/fan and lights?

That's the way it's normally done. All ceiling vent fans that I am aware of are 12-volt appliances.

If I'm boondocking, I need an inverter to run CPAP.

Not really. A CPAP is a DC device. That black box in the OEM cord is a converter. It changes the AC power at the outlet to DC. So... you could wire in an inverter and change the DC juice from the battery to AC with an inverter (and you'd lose about 20% of the power) and then back to DC using the converter in the CPAP's cord. If that sounds goofy...it's because it is.

You'll lose a considerable amount of power. What makes sense is to get a DC cord for your CPAP. That's what I run my Phillips CPAP with.

I also don't use the heated tube when boondocking. It eats up too much power.

Tony

[GTS225]

You'll lose a considerable amount of power. What makes sense is to get a DC cord for your CPAP. That's what I run my Phillips CPAP with.

I also don't use the heated tube when boondocking. It eats up too much power.

Tony

It depends on the machine. I have a ResMed that I use at home, and it's 24vdc, but also have a Phillips machine that's 12vdc. Works great in my 5th wheel.
So you might not need an inverter, and if not, could invest that money into a solar panel and charge controller for boondocking. Look closely at the data tag on the bottom of your machine, or right next to where the cord plugs into it.

Roger

[McFish1951]

Thanks to both of you. Bringing in shore power is a breeze; and getting 12vdc for CPAP sounds quite doable. I can even manage 12 vdc lights and vents fairly easily.

[tony.latham]

It depends on the machine.

I was referring to the 20% power loss from inverters.

Tony

[GTS225]

It depends on the machine.

I was referring to the 20% power loss from inverters.

Tony

And I was referring to input voltage(s) for the CPAP. I did neglect to edit off your first sentence, though. My first machine was a phillips that uses 12vdc for the input. When I qualified for a new machine under Medicare and Tricare rules, the machine I ended up with was a different brand, and that one uses 24vdc input.

I was intending to make sure the OP looked at his machine's input voltage requirements before diving into things too far. Setting up for 12vdc would be bad if his machine is 24vdc.

Roger

[Onajourney]

Except for AC, everything on mine is 12V. I bought a CPAP that runs on 12V. I have a 100AH lithium and can run everything lights, fan, Fridge, CPAP, USB chargers for 3 days without a charge. So with my 200W portable solar panels I can run pretty much indefinitely off grid. I bought a used CPAP for the trailer as they can get pricy.

[tony.latham]

Setting up for 12vdc would be bad if his machine is 24vdc.

But if you purchase the DC cord for the machine, it'll be the correct voltage.

Tony

[H.A.]

I was intending to make sure the OP looked at his machine's input voltage requirements before diving into things too far. Setting up for 12vdc would be bad if his machine is 24vdc.

Fwiw,
There is no end of inexpensive DC to DC boost converters available which magically change 12V into 24V.
Like anything they're not 100% efficient but not nearly as bad as running an AC inverter.

[RJ Howell]

If you require the wattage, then commercial sites are for you. Some National forests have the hookups. Battery up and be prepared. Find places you can charge up for free. I have found several Rest Areas when asked, I could plug into. Many Community grounds as well. By a National Pass and they can also accommodate if asked.

Work out your requirement of wattage and set batteries according to how you can re-charge. DC/DC charging 'I find' my best source. Panels to me are secondary and work, yet I probably don't have the draw you do.. Hell, you use 300 watts of power (what I use in a day) you need to recover that the next. That's 25amps to me and can recover in an hours drive, or ~3hrs of sun.

I can go 3 days with less than a 100a Lion battery (prefer only two). You can do the same as you work out needs and replacement.

I'm heading out on a run and may not be updated on this. You give this group the info, they will figure it out.